During this reporting period, porous support tube work was directed at reducing the firing temperature, where electrically heated furnaces that enable better zone temperature control can be utilized. Work on the air electrode for the FBA cell design has concentrated on modifying the lanthanum manganite, to enhance its conductivity while matching its thermal expansion to that of the other fuel cell components. The thermal expansion and electrical resistivity of La/sub 0/ /sub 5/Ca/sub 0/ /sub 5/MnO/sub 3/ have been determined. An initial FBA cell has been fabricated. Although its performance was below that of the cells in the series cell stack arrangement, it did prove that fabrication of all fuel cell components (including the interconnection) can be accomplished in this cell design. Analytical measurements on an actual HTSOE cell stack have resulted in the use of the differential resistance (..delta..V/..delta..I) to isolate voltage losses under operating conditions, envisaged for the HTSOE fuel cell generator.